Radiosignaling



May 6 1924." 1,493,024

| COHEN ET AL RADIOS IGNALING Filed Aug. 6. 1920 2 Sheets-Sheet 1 May 6 19 24.

L. COHEN ET AL RADIOSIGNALING Filed Au 6 1-920 2 Sheets-Sheet 2 5] vwentoz Patented May 6, 1924.

UNITED STATES PATENT OFFICE.

LOUIS COHEN AND JOSEPH O. MAUBORG-NE, OF WASHINGTON, DISTRICT OF COLUMBIA.

RADIOSIGNALIHG.

Application filed August 6, 1920. Serial No. 401,752.

To all whom it may concern:

Be it known that we, Lotus COHEN and JOSEPH O. MAUBORGNE, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Radiosifgnaling, of which the following is a speci cation.

This invention relates to the art of radio signaling and particularly receiving radio signals and system for use in practicing the same.

The object of the present invention is to eliminate electrostatic disturbances and other interferences in the reception of radio signals and thus improve the clearness and reliability in radio communication.

Our method consists in introducing a resonance wave coil in the antenna circuit. The resonance wave coil which we shall designate hereafter simply as wave coil, is preferably in the form of a long helix uniformly wound with wire, single or multiple layer winding, the electrical constants 0 which, inductance, capacity, and resistance, are of a distributed character, and a wave development is produced on the wave coil by an electrical excitation of the antenna. The wave coil is wound with a large number of turns per unit length, and

'pass throughthe wave coil before reaching the receiving instruments. It is well known that an electrical shock effect such as may be produced by electrostatic disturbances, strays, or near-by radio stations, has a much steeper wave front than the oscillations produced by incoming signals which are regular in the matter of intensity and frequency. The electrical shock effects of Steep wave fronts are more readily attenuated in passing through a conductor on which a wave development is effected by these elec trical disturbances, and as a result, a much higher ratio of signal to static is obtained in the receiving instrument. By suitably adjusting the constants of the Wave coil in the matter of length, number of turns, etc, in

disturbances acting on the antenna in relation to the circuit arrangement. By properly adjusting the length of wire on the wave coil, the position and dimension of the metal tubes, and constants of the loop circuit all in relation to the frequency of the signal to be received, a condition may be .realized where the attenuation of the Signal current is very feeble, while other interfering effects of different-frequencies are attenuated very sharply in their propagation along the Wave coil.

It should also be borne in mind that for the propagation of electrical waves in the free ether, there is one definite fixed relation between the frequency and the wave length, but in the case of propagation of electrical waves along coils, the relation between frequency and wave length is dependent upon the electrical characteristics of the coil, its inductance and its capacity, which also ofiers a means for controlling the wave length. The adjustment of the metal tube and the grounded loop circuit have an equivalent effect as changing the electrical characteristics of the coil, andhence, cause a change in the wave length of any electrical effect propagated along the wave coil. The arrangement involving this invention offers, therefore, a means of controlling both the wave length and the attenuation constant of the wavepropa ated along the wave coil, and by suitable a justments, these properties can be advantageously employed to accentuate the signal to be received and practically nullify all foreign disturbances in their effects upon the detecting instrument.

An additional improvement for the elimination of the'static or other disturbances is provided in a loop circuit introduced in the ground lead of the metal sheath. The

loop circuit is tuned to the frequency of the signals it is desired to receive, thereby offering an extremely high impedance to the signal current, and preventing any of it from leaking away by that path to the ground, but offering a ready path for any other electrical disturbances which are not exactly of the same frequency.

. The circuit combination described above offers a very effective method for increasing greatly the ratio of signal to static thereby improving the clearness and accuracy in radio communication.

The principle of operation and the method of usin our invention can be better understood y reference to the accompany in diagrammatic figures which show typical embodiments of the invention and form part of this specification.

In the accompanying drawings:

Figure 1 is a diagrammatic view of a system for carrying out theinvention in which the receiving circuit is coupled electro-magnetically to the wave coil;

Figure 2 shows an arrangement in which a lumped inductance in series with a condenser, is connected to some point of the wave coil, and the receiving circuit is cou-. pled to that lumped inductance;

Figure 3 shows a modification of our invention in which the detecting instrument is coupledelectrostatically to the wave coil;

Figure 4 shows another embodiment of the invention in which the detecting instrument is coupled'electro-magnetically to the wage coil and a unilateral connection is use i a Figure 5 is similar to Figure 4 except that both ends of the coupled coil are connected to the indicating instrument, and the tuning elements, inductance 2 and capacity 3, are connected in parallel.

I Another embodiment of our invention is shown in Figure 6 in which two wave coils are used, arranged at right angles to each other, to eliminate electro-magnetic reactions between them, the indicating instrument being coupled electro-magnetically to one of these wave coils. Y

Figure 7 is an embodiment of our invention utilizing a combination of the circuit arrangements shown in Figures 2 and 6.

Having more particular reference to the drawings, and in connection with which like characters of reference will designate corresponding parts throughout, in Figure 1,

- the antenna 1 is connected to an inductance '2 in series with a capacity 3 and in series whole is tuned for different frequencies andv is brought into resonance for the frequency of the signal it is desired to receive. The coil 9 which links electrically the detecting instrument to the antenna system, is moved along the wave coil 4 to the 100 of current point on the coil for getting the ighest sen sitiveness. The condenser 19. may be used for the purpose of tuning the circuit includ-' ing coil 9 to the frequency of the incoming signal, thereby still further increasing the selectivity of the system. The loop circuit 6-7, connecting the metal sheath to the ground, is tuned to the frequency of the signal to be received, thereby offering a high impedance path to ground for the signals but a comparatively free path for any other electrical disturbances. I

Any foreign electrical disturbances which may act on the antenna such as electrostatic effects causing a shock excitation of the antenna, are of a steep wave front and in their travel through the wave conductor are rapidly damped out, and in addition are shunted away throu h the loop circuit 6-7, to the ground, there y rendering the receiving instrument comparatively free from these disturbances, and leaving it to respond only to the signals which are to be received.

In Figure 2 a lumped inductance 13 in series with a capacity 13', is connected directly to apoint 20 on the wave coil 4, and the receiving circuit, including the detector, is coupled electro-magnetically through transformer 16 to said inductance 13. The antenna system includin 1, 2, 3, 4, 13, 13, and 8, is tuned as a who e. The connecting point 20 is adjustable along the wave coil 4. The point of connection varies for different signal wave lengths. The loop circuit 67,

and the secondary circuit 1415 are also tuned for the frequency of the signal desired to receive.

Another embodiment of the invention is shown in Figure 3 in which the detecting instrument is coupled electrostatically through a metal ring or band, designated by 17, to a loop of potential point of the wave coil 4 In Figure 4 the indicating instrument is coupled electro-magnetically by means of coil 9 to a loop of current pointofthe wave coil 4. The connection between the conpling coil 9 and indicating instrument; 10' is a unilateral, that is, in case of an electron tube detecting instrument, the grid connection only is used.

Figure 5 is similar to Figure 4 except that both ends of the coupling coil are connected to the indicat' instrument. In the case of an electron tu e detector, the connections are to the grid and the filament, also the tuning elements, inductance 2 and capacity 3 are connected in parallel.

Figure 6 shows still another embodimen of our invention in which two wave coils are used connected electrically but separated from each other and so placed that there is substantially no magnetic reaction between them. One of these wave coils has a metal sheath as described in connection with the previous figures, while the other wave coil 18 is not enclosed in any metal sheath. The indicatin instrument is coupled to the wave coil 18, w ich coupling maybe either electromagnetic or electro-static. The purpose of this arrangement may be stated as follows:

When an electricalimpulse such as an electro-static disturbance, acts on the antenna it sets up a current flow in the wave coil, and though the current at the end of the coil'farthest from the antenna connection is very small, having been attenuated in its passage through the wave coil, nevertheless, the magnetic field set up by that current in the first part of the wave coil, which may be large, reacts upon the distant part of the wave coil and may induce in it considerable current. Splitting the wave coil into two parts, as shown in Figure 6, one of which is designated by 4, and the other one by 18, removes the coil 18 from the influence of the magnetic field produced by the current in the coil 4, and thus further improves the selectivity of the system.

Figure 7 shows an embodiment of our invention which is a modification of the circuit arrangements shown in Figures 2 and 6. Two wave coils 4 and 18 are used and a lumped inductance 13 constituting the primary of the transformer 16 is connected through a condenser 13' to some point 20 of the wave coil 18. This arrangement combines the advantages referred to in connection with the arrangement of Figures 2 and 6.

It is obvious that various modifications of the circuit arrangements ma be made without departi from the spirit of the invention. The l oop circuit 6-7, for instance. shown in all the figuresmay be replaced by a direct ground connection or the metal sheath may be altogether disconnected from the ground and yet not afiect the principle of the invention. Also the tuning elements, the inductance 2, and capacity 3, shown in all the figures, may bev 7 either in series or in glarallel, or may be entirely omitted, depen 'ng upon the relation fications we have shown and referred to the 1 metal sheath 5 as being a metal tube out side the wave coil 4, it is clearly within the province of this invention to replace said sheath by a metal tube inside said Wave coil.

We claim:

1. A system for radio signaling in which the received signals or other electrical effects acting on the antenna are caused to pass through a wave coil before reaching the receiving instruments, said wave coil being enclosed in an adjustable metal sheath, said metal sheath being connected through a loop circuit to the ground, for the purpose of detecting the signals desired to receive.

2. A system for radio signaling in which the received signals or other electrical effects acting on the antenna are caused to pass through two wave coils connected electrically and separated from each other so as not to be within each others magnetic or static fields, one of said wave coils being operatively associated with receiving means. 3. A system for radio signaling in which the received signals or other electrical effects acting on the antenna are caused to pass through two wave coils, connected electrically and separated from each other so as not to be within each others magnetic or static fields, one of said wave coils being enclosed in an adjustable grounded metal sheath and the other of the said Wave coils being operatively associated with receiving means. Y

4. A system of radio signaling comprisin an antenna,tuning elements. a wave coil sald wave coil being operatively associated with an adjustable grounded metal tube, and a detecting instrument connected to said wave coil. 5. A system of radio signaling comprising an antenna, tuning elements, a wave coil, said Wave coil being-enclosed in an adjustable'grounded metal sheath, and a detecting instrument connected electro-magnetically to in an antenna, tuning elements, a wave coil,

said wave coil being enclosed in an adjustable grounded metal sheath, an inductancecapacityecircuit in series, one end ofsaid circuit ing connected to a point on the said wave coil and the other end grounded, a

secondary tuned circuit coupled to the said inductance-capacity circuit and an indicating instrument connected to the said secondary circuit. v

8. A system for radio signaling comprising an antenna, tuning elements, a wave coil, said Wave coil being enclosed in an adjustable metal she-ath, said metal sheath being connected through a loop circuit to the ground, an inductance-capacity circuit in series, one end of said circuit being connected to a point on the said wave coil and the other end of said circuit rounded, a

secondary tuned circuit couple to the said inductance-capacity circuit and an indicating instrument connected to the said secondary circuit.

aeeaoae 9. A system for radio signaling comprising an antenna, two wave coils, connected electrically and separated from each other, one of which is enclosed in an adjustable metal sheath, said metal sheath being connected through a loop-circuit to the ground, an inductance-capacity circuit in series, one end of said circuit being connected to a point on the other of said two wave coils, and the other end of said inductance-capacity circuit being. grounded; a secondary tuned circuit coupled to the said inductance-capacity circuit and an indicating instrument connected to the said secondary circuit.

LOUIS COHEN. J. O. UBQRGNE. 

